Rims for Camera Buttons
The Knife Project tool is an alternative to the boolean. You must constrain the 3D View to an orthographic camera angle in order to get it to work. Think of it as using a light beam which is aligned to your current viewing angle, which then casts a shadow of one object onto another object, to create cuts at all the points of intersection between the two objects. You could use an open-ended cylinder (must be open-ended, or else the projection will be blocked) to create a series of edges defining the button hole. Then you could simply select the all the faces contained within the newly created edges -- as they now form a circle on the surface of the camera -- and extrude them, delete them, or otherwise edit them as needed.
Steps:
Start by making sure you're in Object Mode. Select the cylinder first, then Shift + select the camera body to include it in the selection.

Then, with both selected, Tab into Edit Mode (both objects will remain selected in Edit Mode, which is important). Press whichever numpad key corresponds to the viewing angle that would be perpendicular to your camera's main surface (this is likely to be the Front view, which is accessed by Numpad 1, though Front may actually not be the correct view in your case. You'll have to check). Once the correct view is attained, look to the top of the 3D View for the Mesh Menu. Under it, you'll find Knife Project.

Once this option is chosen, you're done, but it won't look like anything happened. Go back to Object Mode to hide or delete the cylinder. It still won't look like anything happened. Go into Edit Mode, and you will see the new edges made by the cylinder on the surface of the camera body. Edit as needed.